Various types of clamping bands for fixing, for example, a boot for covering a constant-velocity joint of a vehicle have been used. An example of clamping bands has a ring-shaped metallic band section, an outer band part and an inner band part of the band section are overlapped with each other, and engaging claws are engaged with engage holes, so that an inner diameter of the band section is reduced and a member to be clamped, e.g., a boot for covering a constant-velocity joint of a vehicle, can be clamped and fixed.
For example, the outer band part includes a first tool-catching claw, a slit extended from the first tool-catching claw and a plurality of the engage holes. They are formed in that order. The inner band part, which is overlapped with the outer band part, includes a plurality of the engaging claws and a second tool-catching claw. The second tool-catching claw includes an opening section, into which the outer band part can be inserted, and a holding section.
A slide guide tab, which is formed near an inner end of the inner band part, is inserted into a slit guide, which is formed in the outer band part, and one of the engaging claws is released in the slit and the other one is engaged with the engage hole, so that the band section is temporarily engaged and formed into a ring-shape. In this temporarily-clamping state, a tool is engaged with the first tool-catching claw, which is formed near the outer end of the outer band part, and the second tool-catching claw, which is formed in the inner band part, and actuated to move the tool-catching claws close to each other. With this action, the outer end of the outer band part is inserted into the opening section of the second tool-catching claw, and uplift of the outer band part is prevented by the holding section, and the outer band part overrides the engaging claws, which are formed in the inner band part, and then slides and engages the engaging claw with the engage hole. The outer band part is apt to radially outwardly bend, so there is a possibility that the outer end of the outer band part is not guided to the opening section of the second tool-catching claw. Therefore, the slit is extended from the first tool-catching claw formed in the outer band part so as to willfully reduce rigidity, and a curvature of the outer band part is made greater than that of the band section, so that uplift of the outer end of the outer band part can be prevented and the outer end can be securely inserted into the opening section of the second tool-catching claw and retained by the holding section (see Japanese Patent No. 4403728).
In the clamping band disclosed in said Japanese Patent, the first tool-catching claw and the slit, which are formed in the outer band part, are located close to the engage holes, so the outer band part strongly presses the inner band part when the first tool-catching claw and the second tool-catching claw are moved close to each other by the tool, so front ends of the engaging claws of the inner band part will be crushed. Especially, when the outer end of the outer band part is inserted into the opening section of the second tool-catching claw, the outer band part is moved toward the inner band part and pressing force of the outer band part is applied to the engaging claws. Therefore, the engaging claws will be crushed, and the inner band part is apt to buckle. To solve this problem, a prescribed region of the outer band part, which is located between the outer end and a front end wall of the engaging hole on the outer end side, is radially inwardly curved with a curvature greater than that of the band section.
However, by curving the outer band part with the curvature greater than that of the band section, a production cost of the clamping band must be increased. Further, the first tool-catching claw is located close to the engage hole, and the second tool-catching claw is located close to the engaging claw. Therefore, even if the curvature of the outer band part is changed, great drawing force is applied to the engage holes and the engaging claws and great pressing force is radially inwardly applied thereto, so the problem of crushing the front ends of the engaging claws cannot be solved. If the engaging claws are crushed, the engaging claws are easily disengaged from the engaging holes when the inner diameter of the band section is reduced.
To solve the problems, guide sections, which are radially outwardly expanded, are formed at a rear end of the slit and rear ends of the engage holes so as to easily override the engaging claws. But, the production cost of the clamping band must be further increased.